Preparation of highly ordered mesoporous WO 3–TiO 2 as matrix in matrix-assisted laser desorption/ionization mass spectrometry

Abstract

Mesoporous tungsten titanium oxides (MTTO) materials have been synthesized by using triblock copolymer (EO 106PO 70EO 106, Pluronic F127) as a structure-directing agent via “acid–base pairs” strategy. Two different inorganic precursors, tungsten chloride (WCl 6) and titanium isopropoxide [Ti(OPr) 4], were used as the “acid–base pair”. The calcined MTTO materials have been investigated by using XRD, TEM, N 2 adsorption–desorption isotherms and UV-DRS techniques. The XRD and TEM results show that MTTO materials have well-defined two-dimensional (2D) hexagonal mesostructure. The N 2 adsorption–desorption isotherm of the MTTO materials shows that the products have a pore size of 9.8 nm, a pore volume of 0.29 cm 3 g −1 and a BET surface area of 150 m 2 g −1. The UV-DRS spectrum for the MTTO materials reveals that the materials possess maximum absorption at 340 nm. Such materials have been utilized as matrix to detect the peptide (Gramicidin S) by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The results show that the signal intensities of the MALDI-MS spectrum for Gramicidin S with the MTTO materials as matrix are about hundredfold of those obtained with nonporous WO 3–TiO 2 as matrix.